Waves
by MagpieDreamer
Summary: Kat and Boom take a walk on the beach. R&R!


**Waves**

She took him to the beach on Mariner Bay, after they were finished talking to Angela Rawlings about pocket dimensions; some new project Kat was working on.

She kicked off her shoes to wonder along, barefoot, and, out of habit, he did the same. The tide was coming in; their foot prints filled with water where they left them, their heals sank into the sand. It was late afternoon, and the tourists were clearing out for the day, so it wasn't difficult to find a quiet spot by the water's edge.

She picked up a stick, and wrote out the wave equation in the sand. "You see, Boom? That's what it means." And she pointed at the sea, rolling away in front of them, dark blue in the early evening light, then back at the equation in the sand.

"That's a wave?" She'd tried to teach him about this sort of thing before; he still didn't get it.

"That's what it boils down to," she promised.

"No," he pointed at the sea, "_that's_ what it boils down to. You can't turn that into numbers and letters and lines. It's too… it's too…." But he wasn't smart enough to have the words. Too simple, too ugly, too undignified.

Thankfully she'd known him long enough to understand what he meant. She persisted, though, sketching the formula out again, with arrows this time, "you have to understand this, Boom. If you're going to help me, you need to understand how it works."

"Kat, I don't have the brains for this stuff," he gave her a helpless look, "you know that. You know what I'm like."

"But I _do_," she reminded him, gently, "and you're smarter than people give you credit for. They just don't see it."

"I wonder why," he muttered, but she gave him a reproachful look, so he shut up.

"Waves," she handed him the stick, after a moments pause, "you write it out."

"What?"

"The formula. Go on!"

"Alright," he gripped the instrument reluctantly, looked at her diagrams, looked at the patch of sand in front of him. He got as far as Y, before stopping, and shaking his head.

With a deft swipe, he drew a score through the beginnings, and followed it with a long, wavy line.

"There."

"What?"

"It's a wave."

"_Boom_…"

But she laughed, and that was all he needed to hear. She held onto his arm, because that was as close as she ever got to him, and curled her toes in the sand, thinking. Then he copied out the proper formula, anyway, just to please her, but she shook her head.

"It doesn't matter."

"It doesn't?"

"No."

"I don't understand you, sometimes."

"Does that matter?"

"I guess not."

She laughed.

Something about this whole thing seemed to make her happy. He wondered what, but didn't ask. It was best not to push too hard at her mood, in case it broke. If she was happy, he was content, so he let it be.

The sand wasn't too wet, and the tide wouldn't be too close for a few minutes, so they sat down, looking at the equation, and the sea, and kept quiet for a little while. They never did this sort of thing, not normally. Outside of the lab, she didn't look so surreal. Her skin wasn't so translucent, her eyes weren't so green, her hair wasn't so wild. At a distance, you might even mistake her for human (at a great, great distance). He wasn't sure whether it was good for him to be reminded that she could actually exist beyond the sterile walls and electric lighting of the SPD laboratories, or whether it was too disturbing to see her in way that was almost… vulnerable.

"How far away from home are you, Kat?" He asked, because she never talked about where she came from. He wasn't expecting an answer. Or at least, not one that really answered the question.

But she surprised him, "fifteen thousand light years. Give or take."

"Huh." What did you say to that? "You miss it?"

"Every day."

"I miss home, too," he'd been born in Angel Grove, a few thousand miles round the coast, "but I could just get on a bus."

"And I could just get into a space shuttle," she shrugged.

"Why don't you?"

"Why don't _you_?"

"Because. Why don't you?"

"_Because_."

"Yeah."

He found himself grinning, but wasn't sure why. It was a habit he had to work on; grinning when it probably wasn't appropriate. She was picking at the sand under her palm, her knees pulled up under her, weight wresting on her other hand. He'd seen her take up a position like that in her office chair a hundred times, flicking through statistics, trial results, or a good book.

"We should be heading back," she decided, abruptly.

"Okay," he agreed, not because he really wanted to (he didn't), but because he didn't feel like arguing.

They got onto their feet, and left the wave equations on the sand, for the tide to erase when it came in.

Because of the way the bay curved round, the tide had already come in across their exit point, so they had to wade part of the way. The water was cold, but it didn't come up too far; not much past the ankles. Rocks, half buried in the sand and now nearly invisible, were their main obstacle. Twice he stubbed his bare toes and hopped about in pain, causing her a certain amount of amusement, because she was, as ever, the epitome of athletic grace.

Out of annoyance, he kicked the salty water at her, and she leapt out of the way, splashing him far more than he had done her, but laughing in delight at the prospect of a fight. Revenge was difficult to exact on an opponent who could move three times faster than you and harboured the reflexes of a feral cat.

Yet they still ended up chasing each other back across the half-flooded bay, splashing around rather inelegantly as each tried to avoid the other. She made it to the steps off the beach first, and bounded up them, taunting in the way she only ever did when her guard was down. He launched himself after her, aware of how awkward and uncoordinated he was, even in the face of most other humans, let alone her.

Her hands, helping him up the last few steps, as his complete lack of physical fitness caught up with him, signalled a truce, and they sat down in the open door of the SPD truck they had borrowed for the day.

"Well," he decided, still getting his breath back, "that was fun."

She laughed, pushing damp strand of hair out of her eyes, "pointless," she agreed, which was what she always called activities where there was any enjoyment beyond scientific gain. Then she shook her head and wrinkled her nose, "there's sand in my hair!"

"Is there?"

"I can feel it!" She groaned and rubbed at it with her knuckles, "it always takes forever to get out."

He could see how that would be a problem. Her hair was thick and tangled to the point where it seemed almost like a living thing, a fern constantly sprouting new tendrils.

"Sorry," he sighed, feeling truly remorseful.

"I'll forgive you if you recite the wave equation for me."

He leaned across to the window of the truck, hanging at an angle to the door, and blew a line of condensation onto the glass. With his smallest finger, he drew out a wiggly line, and pointed at it.

"Waves."

She laughed, "let's go home, Boom."

"Fifteen thousand light years?"

"The SPD."

"Oh, right, yeah."

He wrote out the real equation anyway, just to keep her happy, as they were pulling out of the parking lot, but she pressed her palm over it to smudge it beyond recognition.

"That's all you need to know, Boom," pointing back towards the sea.

"That water moves?"

"That waves make us happy."

"Cool."

On the beach, the tide drew a filmy cover over their foot prints; a mother, tucking her children in for the night.


End file.
